Improves obsidian platform generation (#2246)

The obsidian platform was not generating constantly in the same spot. It was moving depending on the entrance point (from the sides).
This code changes it, as it will move through relative blocks. 
Also, this change will sync portal and platform center points, which was not done previously. 

Fixes #2239

src/main/java/world/bentobox/bentobox/listeners/teleports/AbstractTeleportListener.java

@@ -19,6 +19,7 @@
 import org.bukkit.Location;
 import org.bukkit.Material;
 import org.bukkit.World;
+import org.bukkit.block.Block;
 import org.bukkit.entity.Player;
 import org.eclipse.jdt.annotation.NonNull;
 import org.eclipse.jdt.annotation.Nullable;
@@ -308,17 +309,28 @@ protected Location calculateLocation(Location fromLocation,
             }
         }
 
-        // Find the maximum x and z corner
-        for (; (i < x + 5) && fromWorld.getBlockAt(i, k, z).getType().equals(Material.END_PORTAL); i++) ;
-        for (; (j < z + 5) && fromWorld.getBlockAt(x, k, j).getType().equals(Material.END_PORTAL); j++) ;
+        // Find the maximum x and z corner using relative block search.
+        Block portalBlock = fromWorld.getBlockAt(i, k, j);
+
+        while (portalBlock.getRelative(1, 0, 0).getType() == Material.END_PORTAL)
+        {
+            portalBlock = portalBlock.getRelative(1, 0, 0);
+            i++;
+        }
+
+        while (portalBlock.getRelative(0, 0, 1).getType() == Material.END_PORTAL)
+        {
+            portalBlock = portalBlock.getRelative(0, 0, 1);
+            j++;
+        }
 
         // Mojang end platform generation is:
         // AIR
         // AIR
         // OBSIDIAN
         // and player is placed on second air block above obsidian.
         // If Y coordinate is below 2, then obsidian platform is not generated and player falls in void.
-        return new Location(toWorld, i, Math.min(toWorld.getMaxHeight() - 2, Math.max(toWorld.getMinHeight() + 2, k)), j);
+        return new Location(toWorld, i - 0.5, Math.min(toWorld.getMaxHeight() - 2, Math.max(toWorld.getMinHeight() + 2, k)), j - 0.5);
     }